Biocidal unsymmetrical di-higher alkyl dimethyl ammonium compounds

ABSTRACT

A METHOD OF INHIBITING MICROORGANISMS BY APPLYING THERETO A WATER-SOLUBLE UNSYMMETRICAL DI-HIGHER ALKYL DIMETHYL AMMONIUM SALT HAVING THE STRUCTURE:   R-N(+)(-R&#39;&#39;)(-CH3)2 X(-)   WHEREIN R AND R&#39;&#39; ARE EITHER STRAIGHT CHAIN OR PREDOMINANTLY STRAIGHT CHAIN BUT DISMISSAL ALKYLS, ONE OF SAID ALKYLS HAVING FROM 9 TO 10 CARBON ATOMS AND THE OTHER HAVING FROM 11 TO 12 CARBON ATOMS, AT LEAST ONE OF THE ALKYLS HAVING AN ODD NUMBER OF CARBONS, AND THE TOTAL SUM OF BOTH ALKYLS BEING BETWEEN 20 AND 21, AND WHEREIN X IS BIOCIDALLY ACCEPTABLE ANION PREFERABLY DERIVED FROM A HALOGEN SUCH AS BROMINE OR CHLORINE, OR WHICH MAY BE METHOSULFATE.

United States Patent 3,730,702 BIOCIDAL UNSYMJVIETRICAL DI-HIGHER ALKYLDllVIETI-IYL AMMONIUM COMPOUNDS Edward G. Shay, Belle Mead, N.J.,Reginald L. Wakeman, Philadelphia, Pa., and Alphonso N. Petrocci, GlenRock, N..l., asisgnors to Millmaster Onyx Corporation, New York, N.Y.

No Drawing. Continuation-impart of abandoned application Ser. No.782,439, Dec. 9, 1968. This application June 9, 1971, Ser. No. 151,583

Int. Cl. A01n 9/20 US. C]. 7167 1 Claim ABSTRACT OF THE DISCLOSURE Amethod of inhibiting microorganisms by applying thereto a water-solubleunsymmetrical di-higher alkyl dimethyl ammonium salt having thestructure:

wherein R and R are either straight chain or predominantly straightchain but dissimilar alkyls, one of said alkyls having from 9 to 10carbon atoms and the other having from 11 to 12 carbon atoms, at leastone of the alkyls having an odd number of carbons, and the total sum ofboth alkyls being between and 21; and wherein X is a biocidallyacceptable anion preferably derived from a halogen such as bromine orchlorine, or which may be methosulfate.

This is a continuation-in-part of co-pending application Ser. No.782,439, filed Dec. 9, 1968, now abandoned.

This invention relates to the biocidal use of certain water-solubleunsymmetrical (ii-higher alkyl dimethyl ammonium salts.

Although many compounds including a wide variety of quaternary ammoniumsalts having higher alkyl groups have very effective biocidalactivities, it has been found that, in general, such biocidal activitiesare substantially inhibited or sometimes even totally suppressed whensuch compounds are used in hard water.

The term hard water is generally used to describe water having anappreciable amount of carbonates, bicarbonates, sulfates and chloridesof calcium and magnesium, and sometimes also of iron. The term hardwater also includes the possible presence of alkaline earths and heavymetal ions in general. By appreciable amoun is meant at least about 75p.p.m. to about 500 p.p.m. Very hard water is that which contains over1,000 p.p.m.

It is particularly important that such hard water resistant quaternariesbe employed where the time of contact is short, as in the sanitizationof utensils, for example in the dairy industry, restaurants and bars,and in the washing of eggs, fruits and vegetables in order to preventthe spread of infection. In general, these compounds are effective forsanitization of surfaces wherever they can feasibly be used.

In accordance with the present invention, it has now been discoveredthat certain unsymmetrical di-higher alkyl dimethyl ammonium salts whichare water-soluble, and particularly their bromides and chlorides and, tosome extent, their methosulfates, remain biocidally effective even invery hard water, where the content of the contaminants is above 750p.p.m. On the other hand, other closely related homologs show littlebiocidal effectiveness in hard water even where the amount of the icecontaminants is considerably lower. These salts have the structure:

R CH3 i r- R/ CHs wherein R and R are either straight chain orpredominantly straight chain but dissimilar alkyls, one of said alkylshaving from 9 to 10 carbon atoms and the other having from 11 to 12carbon atoms, at least one of the alkyls having an odd number ofcarbons, and the total sum of both alkyls being between 20 and 21; andwherein X is a biocidally acceptable anion preferably derived from ahalogen such as bromine or chlorine. It is also possible to usemethosulfate, although much less preferable since the results are not aseffective and the compounds are somewhat more difficult to make.

It is possible to use, as the straight chain or predominantly straightchain alcohols such as may be obtained by the oxo-reaction ofalpha-olefins. For example, an oxo-derived alcohol containing about 20%by weight C12, C13, C14 and by weight C may be converted to a tertiaryamine and quaternized. Decene-l may be converted to a C amine via the Coxo-alcohol.

The biocides of the present invention are effective in very hard waterin a concentration of the biocide of between about 100 to 1,000 p.p.m.The preferred and most effective range is about 200 to 400 p.p.m.

The present compounds are all easily prepared in various manners. Thefollowing examples are illustrative of their preparation.

EXAMPLE 1 Equimolecular amounts of dodecyl dimethyl amine and nonylbromide were missed with an amount of 99% isopropanol equal to about theweight of the mixture of the amine and the bromide. The mixture was thenheated at the reflux temperature (about 88 to 90 C.) and at atmosphericpressure for a period of about eight hours, or until thereactionappeared to be complete. It was determined by argentometrictitration that the yield was about 90% complete after five hours, andessentially complete (about 98-99%) overnight on the steam bath. Theprodnot was then cooled to room temperature and the concentrationadjusted to 50 weight percent by the addition of 99% isopropanol.

EXAMPLE 2 In the same manner as in Example 1, dodecyl bromide wasreacted with nonyl dimethyl amine, to yield the same product as that ofExample 1.

EXAMPLE 3 In a similar manner to Examples 1 and 2, the corre spondingalkyl chlorides were substituted for the corresponding alkyl bromides ineach instance, and the reactions were carried essentially to completionto yield nonyl dodecyl ammonium chloride in each instance.

EXAMPLE 4 Using the same procedures as in Examples 1, 2 and 3, and usingthe same reaction conditions, the di-higher alkyl dimethyl ammoniumbromides shown in Tables I and II hereinafter, as well as thecorresponding chlorides, were prepared from the corresponding al-kyldimethyl amines and alkyl bromides and chlorides.

The aforesaid unsymmetrical quaternary ammonium compounds may also beprepared by a two-stage process whereby an unsymmetrical di-higher alkylmonomethyl amine is first prepared by the interaction of an alkyl halidesuch as chloride or bromide, and an alkyl monomethyl amnie. Then afterliberating the tertiary amine, by treatment with a caustic, from itshydrohalide salt, the tertiary amine is quaternized by reaction with analkylating agent. This is illustrated in Examples and 6 as follows:

EXAMPLE 5 Equimolecular amounts of dodecyl monomethyl amine and nonylbromide were mixed with an amount of 99% isopropanol equal to about thecombined weight of the amine and the bromide. The mixture was thenheated at about 90 C., under agitation and under reflux, at atomsphericpressure, for a period of hours until the reaction was essentiallycomplete as indicated by argentometric titration of the bromide ion. Thesolution was then mixed with about twice its volume of water plus about1 to 1.2 molecular equivalent of NaOH. The liberated tertiary amine(nonyl dodecyl monomethyl amine) was then separated in a separatoryfunnel, washed with water, and dried.

EXAMPLE 6 The tertiary amine of Example 5 was quaternized by reactionwith methyl chloride, in an agitated pressure vessel at about 90 C., ina medium of 99% isopropanol, along with about 3% of water and 0.5% ofsodium bicarbonate as an acid acceptor. Methyl chloride was then passedinto the vessel at such a rate as to maintain a pres sure of less than30 p.s.i. in the reactor, the addition of the methyl chloride beingcontinued until no further reaction occurred, as indicated by failure ofthe pressure to fall when the methyl chloride supply was cut off.

About midway in the addition of the methyl chloride, an additional 0.5of sodium bicarbonate was added, to take up any traces of HCl that mighthave been formed.

Agitation and heating were then continued for about two hours longer,after which the reaction mass was cooled to about 50 C., and was thenfiltered to remove the salts. The concentration was then adjusted to 50%by the addition of 99% isopropanol, the resulting product being nonyldodecyl dimethyl ammonium chloride.

The corresponding bromide was prepared in a similar manner by reactingthe tertiary amine with methyl bromide at about 5055 C., at aboutatmospheric pressure.

EXAMPLE 7 A process similar to Example 6 was used to obtain thecorresponding methosulfatc, except that the reaction was conducted atabout 60 C. and a stochiometric amount of dimethyl sulfate was used asthe reactant.

It is also within the scope of the present invention to react analcohol, either straight or branched chain, such as those obtained byoxo reactions of alpha-olefins, with a suitable halogenating agent, bymethods known to the art, to form the corresponding alkyl halide, eitherstraight or branched chain, or mixtures thereof. Such alkyl halide maythen be employed as a quaternizing agent for the tertiary amines, or itmay be reacted with either monomethyl amine or dimethyl amine to formthe corresponding higher alkyl monomethyl amine or higher alkyl dimethylamine. It It may thereafter be reacted according to the foregoingexamples to yield the unsymmetrical di-higher alkyl dimethyl ammoniumquaternary salts of this invention. This type of reaction is shown bythe following example.

EXAMPLE 8 The alochol derived by the oxo reaction from decene-l, whichyields a mixture of n-undecanol and alpha-methyl decanol, washalogenated by reaction with hydrogen chloride to yield the undecylchloride. This chloride was then reacted with dodecyl monomethyl aminein the manner de scribed in Example 5 to form undecyl dodecyl monomethylamine. This was quaternized by reaction with methyl chloride in the samemanner described in Example 6, to yield the unsymmetrical di-higheralkyl dimethyl ammonium salt.

In all the above examples, any desirable alcohol other than isopropanolmay be used, or any other feasible solvent may be substituted.

The unexpectedly high biocidal activity in very hard water of theseunsymmetrical di-higher alkyl dimethyl ammonium salts having at leastone odd-carbon chain and a sum total of from 20 to 22 carbons in thesaid alkyls is illustrated by the following table, in which theirperformance is compared with the closest homologous symmetrical dialkyldimethyl ammonium salts, as well as certain unsymmetrical homologs ofdifferent carbon ranges. The test method used was the Methods ofAnalysis of the Association of Ofiicial Analytical Chemists, 10thedition published by that organization in 1965, and contained in pages87-89, a copy of which is enclosed.

The organism used was Escherichia coli, the inoculum containing aconcentration of the organism in the order of 100,000,000 permilliliter.

In each case, the compound used was the bromide salt.

TABLE I.HARD WATER TOLERANCE IN P.P.M. (AT 200 P.P.M. QUATERNARY)UNSYMMETRICAL DIALKYL DIMETHYL QUATERNARIES Carbons in other alkylCarbons in one alkyl 6 7 8 9 10 The product of this invention may beused for the disinfection or sanitization of hard surfaces; for thesanitization of textile and other fabrics; as topical antiseptics; inwater treatment; and for other bactericidal, fungicidal and algacidalpurposes where quaternary ammonium compounds are compatible.

When mixed with an equal amount of a non-ionic surfactant, such as alkylphenol ethoxylate, the products retain a substantial proportion of theirefiicacy. They also remain substantially potent in the presence of smallamounts of anionic surfactants or the protein.

The invention claimed is:

1. A method of disinfecting or sanitizing hard surfaces, fabrics,topical portions of the body, and water, which comprises applyingthereto a bactericidally, fungicidally or algacidally effective amountof a compound of the structure:

R CH3 I: R'/ OHa wherein R and R are straight chain or predominantlystraight chain alkyls, one of said alkyls having 9 carbon atoms and theother of said alkyls having 11 carbon atoms, and X being a member of thegroup consisting of chloride, bromide and methosulfate.

References Cited UNITED STATES PATENTS 3,054,678 9/ 1962 Michener et al424-329 FOREIGN PATENTS 6802352 8/1968 Holland 424-329 ALBERT T. MEYERS,Primary Examiner F. E. WADDELL, Assistant Examiner US. Cl. X.R. 424-329

